Field of the Invention
The invention relates to a riveting tool for setting blind rivet nuts and/or blind rivet screws, comprising                a drive piston which is able to be hydraulically adjusted from an initial position toward an end position and        a drawing mandrel which is able to be brought releasably into operative connection with the drive piston and which is able to be adjusted by the drive piston between a rivet receiving position and a setting position.        
Description of Related Art
Blind rivet nuts and/or blind rivet screws are rivets which have a thread and which, for example, are used when a lower face, an inner face or a rear face of a component is not accessible or only accessible with difficulty, as is the case for example with pipes. Blind rivet nuts and/or blind rivet screws thus provide the opportunity of applying threads to components if said components have a wall thickness which is too small in order to permit the cutting of threads.
Riveting tools of the type mentioned in the introduction are used in order to fasten the blind rivet nuts and/or blind rivet screws in a convenient manner to the respective component. The rivet to be set is arranged by a defined deformation on the component by the drawing mandrel which is adjustable between the rivet receiving position and the setting position and which is connected to the drive piston of the riveting tool, said drawing mandrel having an internal or external thread which is respectively adapted to the rivet to be set. For setting the blind rivet nuts and/or the blind rivet screws, these are previously screwed onto the drawing mandrel, introduced into the previously produced opening of the component for receiving the rivet and set by the stroke of the drawing mandrel applied by the riveting tool, wherein the rivet in this case is supported on a setting head on the riveting tool.
In this case, the length of the setting movement which is determined by the adjustment path of the drawing mandrel connected to the drive piston is essential for the quality of the connection between the set rivet and the component. The adjustment path, i.e. the stroke path of the drawing mandrel from the rivet receiving position into the setting position, determines the strength of the connection of the component and rivet. The adjustment path in this case is dependent, amongst other things, on the material thickness of the components as well as the rivet used. Generally, the adjustment path in this case is controlled via hydraulic pressure. The setting movement is terminated, for example, by an automated or manual switching-off of a pump unit, if a preset pressure, which corresponds to a defined position of the drawing mandrel, is reached.
Such a pressure-controlled setting of rivets, however, has the drawback that, in particular in the case of a manual interruption to the setting process by the operator when reaching a preset pressure—it leads to setting processes of variable quality. Proceeding therefrom the object of the invention is to provide a riveting tool of the type mentioned in the introduction by which uniform setting processes of rivets may be carried out with a high degree of repeated accuracy.